After news outlets reported this, the ISIS-affiliated Amaq news
agency released a statement on its online propaganda channels
claiming responsibility for the attack.

But the statement differed from those released after recent
ISIS-claimed attacks in Paris and Brussels. In the Amaq statement
released Sunday, the ISIS link to the Orlando attack was
attributed to a "source." The brief statement also did not
describe or provide any details about the attack.

While the Paris and Brussels attackers had direct ties to ISIS
leaders, it's unclear how closely Mateen is connected to the
group.

Michael Horowitz, a geopolitical and security analyst at the
Levantine Group, a Middle East-based risk consultancy, told
Business Insider that there had yet to be anything "that even
remotely proves the attacker was in contact with ISIS."

Horowitz said in an email:

The Amaq statement provides very little details regarding the
attack, and even uses a relatively cautious phrasing by saying
'source to al-Amaq,' suggesting the group had no prior knowledge
of the attack. The statement also refrains from directly saying
that ISIS is responsible for the attack but rather indicates that
'an Islamic State fighter' carried out the attack. Both these
elements suggest the attack was ISIS-inspired rather than
directed or financed by the group.

Rita Katz, an expert on ISIS propaganda and cofounder of the SITE
Intelligence Group, made a similar assessment.

"There is no doubt that this message from Amaq is different than
the claim after the Brussels attack," she told Business Insider
in an email. "ISIS' Amaq message claim that shooter, Omar Mateen,
is an ISIS fighter, seems to be based on the media reports that
he pledged to ISIS."

Police
forensics investigators at the crime scene of the Pulse
nightclub.REUTERS/Carlo
Allegri

The method in which the statement was released is also unusual.
For past attacks, ISIS has released official statements that are
directly from the group rather than from the ISIS-linked Amaq,
which
acts as a news service for ISIS but is not officially part of
the terrorist group's media wing.

"A direct statement from ISIS would have had more weight,"
Horowitz said.

"It is not uncommon for ISIS to release its first — and sometimes
only — claim via al-Amaq, yet major 'operations' such as the
Paris attack or the downing of the Russian plane [in Egypt] have
been claimed through official ISIS statements first, and later an
al-Amaq communique."

The social-media response from ISIS supporters has also been
muted compared with past attacks.

"ISIS supporters praised the attack on social media, however,
there is no overwhelming output from pro-ISIS media groups" as
there was after the Paris and Brussels massacres, Katz said.

This further indicates that the Orlando shooting is likely to be
a "lone wolf attack and was not coordinated with ISIS leadership
as an ISIS operation," she noted.

Weapons
and other evidence on a tarp in San Bernardino,
California.REUTERS/Mario
Anzuoni

The lone-wolf strategy

ISIS' leadership has showed it does not need to have had a direct
role in planning an attack to claim the attack as its own. Such
was the case in the shooting in San Bernardino, California, last
year, which was
carried out by ISIS supporters.

"With the ISIS accepting all who pledge to it, the Amaq report on
the shooter being an IS fighter doesn't necessarily mean he
coordinated with the IS prior to the attack, but acted in their
name and they accept it as their own," Katz said.

ISIS has been encouraging so-called lone-wolf attacks as it loses
ground in the Middle East. Much of the group's recruitment
efforts are based on the message that ISIS is "remaining and
expanding" — thousands of foreign fighters flocked to ISIS' de
facto capital of Raqqa, Syria, when the group looked like an
unstoppable force.

But that message has been damaged recently as ground forces
backed by a US-led coalition have succeeded in taking back
territory from the group. Thus, to maintain its powerful image,
ISIS has started relying more on external attacks.

The group has gone from calling all Muslims to come to its
self-declared caliphate in the Middle East to encouraging its
supporters to remain in their home countries and commit attacks
there.

Last month, ISIS spokesman Abu Muhammad al-Adnani
released an audio message calling on ISIS supporters to mount
attacks in Western countries.

"The smallest action you do in their heartland is better and more
enduring to us than what you would if you were with us," Adnani
said in the statement. "If one of you hoped to reach the Islamic
State, we wish we were in your place to punish the Crusaders day
and night."

Adnani also noted that some supporters were reluctant to kill
civilians. He then provided justification.

"Know that inside the lands of the belligerent crusaders, there
is no sanctity of blood and no existence of those called
'innocents,'" Adnani said. "Know that your targeting those who
are called 'civilians' is more beloved to us and more effective,
as it is more harmful, painful, and a greater deterrent to them."

Reuters

Horowitz noted that these messages could be effective as calls to
action for radicalized people.

"These messages by ISIS's leadership are meant to maximize the
psychological impact of these attacks among the Western public,"
he said.

"They create the perception that ISIS does control these attacks
from within the 'safety' of its Caliphate in Iraq and Syria. In
general, however, ISIS has little control over these radicalized
individuals, other than pushing them to act within a specific
timeframe."

And ISIS might have seen this latest attack as an opportunity to
claim a success story on US soil.

"For the first time, the group seems to be 'taking a risk' by
claiming an attack without being fully aware of the surroundings
of the alleged 'pledge of allegiance,'" Horowitz said. "This may
stem from the group's situation, as it faces multiple offensives
in Iraq and Syria, and would also explain the phrasing 'source to
al-Amaq' before the statement."

Horowitz said
on Twitter that ISIS haste in claiming the attack showed
"just how much the group was waiting for it to boost its morale
as it faces multiple offensives" in the Middle East.

Mateen was known to US law enforcement. He was on an FBI list of
suspected ISIS sympathizers, and federal authorities had looked
into him in 2013 and 2014, officials said Sunday.